After a 20 years absence, I have a new 10 gallon fairly heavily planted tank. While cycling I had the lights on (26 watts CFL, 5800ºK) for 12 hours. Of course, I got an algae bloom. I learned my ways and reduced my lighting to 8 hours, and I started using Excel Flourish.

The algae is no longer a problem, my tank has been declared as being completely cycled by the tests my LFS did for me, and and the fish I have are happy, but I am not. I want my lights on more so I can enjoy seeing the plants... and fish!

So, I have two questions...

1. How many hours can I keep my lights on and not get an algae bloom?

2. Can I divide those hours and have a dark period in the middle of the day so I can see the tank more in the evening?

The general guideline is to have the light on for 8-12 hours. Closer to 12 hours if you are growing out your plants and closer to 8 if you are maintaining your scape and/or fighting algae. I tend to run mine for 10 hours and find it to be a nice balance.

You can add a seista to your photo period for extended viewing. Some believe that this also reduces algae, but I've never seen any evidence of it. I prefer to have the light on for a single photo period and just have it set so that it's on the most when I'm around to view them.

I have (today) changed my photo period to 9 hours. I think I will see how that goes and move up to 10 hours as you do next week. Still curious about split photo periods and any real world experiences with them.

I'm not sure, havent tried it yet. I'm interested in it. It seems its 50/50, some say it works great for algae control others say why bother.

One thing against it IMO is using flourescent lighting. Flourescent bulbs like to stay on. The ballast puts lots of current through them at startup to get them going, then it drops back to the normal wattage. This effects the bulb life, more startups is harder on the bulbs then hours running. Meaning the bulbs will go bad sooner. So starting them up 2x per day instead of 1, I'm not sure that it will be a direct 50% bulb life decrease but if keeping the same total lights on hours it may very well be close.

That being said most people replace bulbs before they burn out due to spectrum shifting. So I'm guessing that turning them on 2x as much, using the higher current would prob aid in shifting the spectrum sooner also.

This means that for growing plants, the split period/"siesta" prob wears the bulbs out faster.

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10G,Planted- Endler's Livebearers+RCS, 55G,planted

Quote:

Originally Posted by Kurt_Nelson

Understanding the basics will let you make informed decisions on what advice to follow, and what advice is just plain hooey!

I'm not sure, havent tried it yet. I'm interested in it. It seems its 50/50, some say it works great for algae control others say why bother.

One thing against it IMO is using flourescent lighting. Flourescent bulbs like to stay on. The ballast puts lots of current through them at startup to get them going, then it drops back to the normal wattage. This effects the bulb life, more startups is harder on the bulbs then hours running. Meaning the bulbs will go bad sooner. So starting them up 2x per day instead of 1, I'm not sure that it will be a direct 50% bulb life decrease but if keeping the same total lights on hours it may very well be close.

That being said most people replace bulbs before they burn out due to spectrum shifting. So I'm guessing that turning them on 2x as much, using the higher current would prob aid in shifting the spectrum sooner. Meaning that for growing plants it prob wears the bulbs out faster like mentioned above.